1. Field of the Invention
The present invention relates to an improved power washer wand and, more particularly, to a power washer wand having a loop which greatly reduces the back pressure exerted on the user.
2. Discussion of Related Art
Power washing, or pressure washing, is commonly used in the maintenance of buildings and other exterior surfaces. Power washing is typically performed using a device such as is seen in FIG. 1. A power washing machine 5 typically includes a pump 7 connected to a water source 9, and a wand 11 which is connected to the pump 7 by a hose 13. The power washer user holds the power washer wand 11 and activates a trigger 15 to expel from a nozzle or tip 17 a highly pressurized water stream against a surface. This highly pressurized water stream is typically used to remove dirt, mildew, and other unwanted substances from a surface.
One well-known drawback of power washing is the back pressure exerted from the highly pressurized water stream to the user. This back pressure has several drawbacks.
A first drawback is that the back pressure prevents the user from standing on the ground and extending his arms to reach high or distant surfaces. The pressure exerted from the surface and through the wand increases exponentially as it extends down a straight line. If a user extends his arm to wash a distant surface, the force from the water against the surface to the user's shoulder is much greater than, for example, the force from the surface to the user's elbow. Note that the pressure of the water stream against the surface may exceed 2000 lb/in.sup.2 and the distance from the surface to the user's shoulder (i.e., has extended his arm) may exceed 6 feet. Thus, the pressure exerted on the user's shoulder may be great. Consequently, the user may need to erect a scaffold or ladder from which distant surfaces may be reached without the user extending his arm. This is inconvenient, time consuming--and expensive if a ladder or scaffold is not available. Moreover, this is dangerous. The back pressure exerted by the water stream may cause the user to fall from the ladder or scaffold. In some cases, some surfaces may not be reached even if a ladder or scaffold is used.
A second drawback is that the back pressure limits the size of the wand. Because the straight length from the surface through a straight line exponentially increases the force on the user, a long wand is difficult to operate. Thus, a wand for use with a high pressure nozzle cannot be made longer than several feet because the pressure from the surface being power washed to the user's elbow (or even to the trigger) is too great for convenient use. Similarly, a wand for use with a high pressure nozzle cannot be connected to an extension, again because the forces on the user holding the proximal end of the wand/extension combination are too great.
A typical wand 11 is connected to the hose 13 using a conventional "quick coupler" 19. If an extended wand was constructed of a number of portions connected using only conventional quick couplings, the extension would not be safe. This is because the back pressure exerted on the couplings would greatly stress the couplings and could result in the extension breaking during use. Telescopic wands are known. However, these telescopic wands are intended for use only with low pressure nozzles. For example, a low pressure nozzle may have a 25.degree. "fan out". As seen in FIG. 2A, a tip 17' having a large "fan out" distributes the water W along a large area of the surface being cleaned. As a result, the pressure against the surface is reduced. At the same time, the effectiveness of the power washer to remove unwanted substances from the surface is also reduced. On the other hand, as seen in FIG. 2B, nozzles having little or no "fan out", such as a 0.degree. nozzle 17", focus all of the water stream's pressure on a small area of the surface being cleaned and thus are more effective at removing unwanted substances from the surface. For the reasons described above, however, a telescopic wand cannot practically be used with a high pressure nozzle.
A third drawback is that the back pressure tends to fatigue the user. The user exerts energy against this back pressure in order to hold the wand 11 steady.
Therefore, it is an object of the present invention to provide a power washer wand which reduces the back pressure caused by the water stream.
It is a further object of the present invention to provide a power washer which may be used to reach distant surfaces without the use of a scaffold or ladder.
It is yet a further object of the present invention to provide a power washer wand which may have an extended length without any compromise in nozzle pressure.
It is an even further object of the present invention to provide an improved extended wand.